Electric spray-gun



Oct. 29, 1957 T. KRf'EBs' 2,811,391

ELECTRIC SPRAY-GUN Filed Dec, 10, 1953 Z5 Sheets-Sheet l wir" JW f oct. 29, 1957 T. @EBS 2,811,391

ELECTRIC- SPRAY-GUN Filed Dec. l0, 1953 5 Sheets-Sheet 2 Oct. 29, 1957 T. KREBs ELECTRIC SPRAY-GUN 5 Sheets-Sheet 5 Filed Deo. l0, 1953 Unite rates Patent O ELECTRIC SPRAY-GUN Theodor Krebs, Oberbuchsiten, Switzerland Application December 10, 1953, Serial No. 397,383

Claims priority, application Switzerland December 10, 1952 14 Claims. (Cl. 299-97) The invention relates to an electric spray-gun. The material to be sprayed has hitherto been broken down into extremely small particles by means of compressed air and projected on to the article to be sprayed. In order to be able to carry this process into effect, it is necessary to have a complete plant for generating compressed air and in addition, when spraying with compressed air, the material being sprayed is in part produced in the form of a mist which does not reach the article to be sprayed and consequently represents a loss of material. Frequently, when working with liquids of diierent viscosities, it is necessary to have dimensions of the nozzle apertures which are between those of the spraying nozzles which are actually available; accordingly, the best atomisation cannot always be achieved with a limited number of spraying nozzles. Furthermore, the size of the storage chamber which is provided in the spray gun for the liquid under pressure has a certain intiuence on the construction of the spraying nozzle. Finally, the satisfactory operation of the spray-gun is generally also substantially dependent on the moving parts of the spray-gun operating as far as possible without friction.

The subject of the invention is characterised by the fact that a pressure pump supplies the pressure required for spraying the material directly, without interposition of compressed air, and that the piston of this pressure pump is actuated by an oscillating armature which is moved electromagnetically, which piston delivers the liquid under pressure into a storage chamber from which the said liquid ilows into the spraying nozzle.

Constructional examples of the subject of the invention are shown by way of example in the accompanying drawings, wherein:

Figure 1 is a section through the longitudinal axis of the pressure pump and a front view of the oscillating armature and the magnet after partly breaking away the cover;

Figure 2 is a longitudinal section of a second embodiment taken through the pump axis and the middle of the electromagnet;

Figure 3 is a longitudinal section through a third embodiment of the oscillating armature arrangement;

Figure 4 is a front View, with the oscillating armature shown partly in section along the line A-B of Figure 3;

Figure 5 is a longitudinal section of the spraying nozzle to a larger scale;

Figure 6 is a longitudinal section of a second embodiment of the spraying nozzle;

Figure 7 is a longitudinal section of a third embodiment of the spraying nozzle; and

Figure 8 is a side elevation of the spray-gun with the spraying nozzle according to Figure 7, shown partly in section, screwed thereon.

ln the figures, the housing of the spray-gun is indicated at 1. 4 is the bundle of laminations and 4b is the coil of the electromagnet 23; Sis the oscillating armature. The upper end of the oscillating armature bears at that side which facesl the electromagnet and which is arranged in y "ice the rear part of the spray-gun, against a thrust bolt 8 which is displaceably mounted in a guide member 9 and which transmits the oscillations of the oscillating armature to the piston 10 of the pressure pump built into the front part of the spray-gun. That outer end of the piston 10 of the pressure pump which is constructed as a head bears against that end of the thrust bolt 8 which is disposed remote from the upper end of the oscillating armature 5. A return spring 11 is arranged between the inner end of the piston head of the pressure pump and the inner end face of the pressure pump cylinder 12. In that part of the pressure pump cylinder 12 which is disposed on the outside is a pressure valve which consists of a ball 13 bearing under the action of the spring 14 on the valve seat inside the pump cylinder. The conical outer end of the suction pipe 18, which is screwed into the container mounting 2 secured to the front of the spray-gun on the underside, is positioned in a conical hole of the pressure pump cylinder 12, which hole is formed in the middle portion of the said cylinder at right angles to its longitudinal axis and extends as far as its cylinder space 12a. That end of the suction pipe which is disposed inside the container 15 is bent over at an angle. 16 is a pressure-equalising pipe which extends through the container mounting 2 into the container 15. The pressure pump cylinder 12 is secured against displacement along its longitudinal axis by the conical outer end of the suction pipe 18.

That contact surface 4a of the electromagnet which faces the oscillating armature 5 enclo-ses, with the pump piston axis, an angle a which is determined by the end position of the oscillating armature 5 in its contactmaking position. In the constructional example according to Figure 2 and also those according to Figures 3 and- 4, this angle is more than The oscillating armature 5 is provided at its bottom end remote from the thrust bolt 8 of the pump piston 10 with a bearing which is nondisplaceable in a planeV disposed parallel to its Contact surface. Y

In the constructional example according to Figure I, one side of the bottom end of the oscillatingl armature 5 bears against the bottom end of the bundle of laminations 4 of the elctromagnet 23, while the opposite side of the bottom end of the oscillating armature 5 is secured against displacement by meansk of a pin 5a resiliently supported r by the spring 5b, said pin being guided in a bore Se of the housing, it being possible for the tension of the spring 5b to be adjusted by a screw 5f fitted in the said bore.

In the constructional example according to Figure 2, one side of the bottom end of the oscillating armature 5 bears against the bottom end face of the bundle of laminations 4 of the electromagnet 23, while the opposite side is formed with a spherical depression 5d in which bears the spherical end of a pin 5a which is guided in the bore 5e of abolt 5f screwed into the housing, and the bottom end of the oscillating armature 5 is urged against the bottom end of the bundle of laminations 4 of the electromagnet 23 by means of a spring 5b provided in the said bore.

In the constructional example according to Figure l, the upper end of the oscillating armature 5 is provided `on that side facing the bundle of laminations 4 of the electromagnet 23 with a longitudinal slot 5c in which engages the thrust bolt 8. Bearing against that spherical depression in the oscillating armature which is opposite the said longitudinal slot 5c in said armatureV 5 is the spherical end of an adjusting bolt 24, which is fitted inside an adjusting screw 6- andv is. guided in the head thereof. Positioned inside this adjusting screw 6 is the adjusting spring 7 by whichthe spherical end of the adjusting` bolt 24Y is urged with greater or lesser force against thev oscillating armature by turning the adjusting screw 6,.y

In contrast to the constructional example according to Figure l, the upper end of the Voscillatingv armature in the construction according to Figure 2 is reduced as far as its centre 5g Ion the side thereof facing the thrust bolt 8 and is formed in this surface 5g with a longitudinal slot 5c which is engaged by the thrust bolt 8. The spherical end of the adjusting bolt 24 bears on that at side 5h of the oscillating armature 5 which is opposite the said longitudinal slot, said bolt being'reduced in diameter to accommodate the adjusting spring 7 and being guided at its inner and outer ends in the adjusting screw 6 which is capable of being adjusted by a threaded connection in the housing. I

In contrast to the constructional example according to Figure 2, the bottom extended end of the oscillating armature 5 in the construction according to Figures 3 and 4 is pivotally connected by means of the shaft 5k to a pin 5a which is guided in the bore 5e of a bolt 5f which is in screw-threaded connection with the housing. Under the action of a spring 5b provided in the said bore, the bottom end of the oscillating armature 5 is urged by means of the pin 5a against the bottom end of the bundle of laminations 4 of the electromagnet 23.

In this constructional example, the upper end of the oscillating armature Sis provided on its side facing the thrust bolt 8 with a longitudinal slot 5c which is engaged by the thrust bolt 8 and is cut away as far as its centre line 5h on the side thereof opposite the said slot. Bearing against this cut-away flat side 5h of the oscillating armature 5 is the spherical end of the adjusting bolt 24 which is reduced in diameter to accommodate the adjusting spring 7 and is guided at its inner and outer ends in the adjusting screw 6 which is adapted to be adjusted by the screw-threaded connection in the housing.

In the constructional example according to Figure l, the outer end of the pressure pump cylinder 12 is closed by a locking nut 3 in which is located the cylindrical spraying nozzle 3a which is drilled out longitudinally thereof; provided at the inner end of this bore is a transverse bore which leads outwardly. Swirl grooves arranged at right-angles to one another and eccentrically with respect to the longitudinal axis of the nozzle are formed in the said nozzle on the end thereof facing the spraying hole formed in the end face of the nut. 3b is a sealing ring for the spraying nozzle.

The constructional example' according to Figure 5 shows a spraying nozzle in which there is provided at the end of the pressure pump cylinder a locking nut in which is fitted the cylindrical spraying nozzle 3a, which closes the swirl chamber 3f by means of its end facing the nozzle hole 3e and is formed on the edge thereof contacting the inside surface of the chamber :along a circular line 3c with a large number of notches arranged eccentrically with respect to the nozzle axis. That edge of the cylindrical spraying nozzle element 3a which contacts the conical inside surface of the chamber 3f on a circular line 3c is provided in the present constructional example with at least six notches which open into the chamber 3f at a predetermined angle to the radius which is dened by the outer entrance point of the notches.

A modification of the constructional example according to Figure 5 is shown in Figure 6, in which the outer end of the pressure pump cylinder also has a locking nut 3 provided thereon, the said cylindrical spraying nozzle 3a again being disposed in the said nut. The said nut is formed at its outer end with a removable cap 3d in which is located a part of the swirl chamber 3f and the nozzle hole 3e. In the present constructional example, the cap 3d has a screw-threaded connection with the nut.

Figures 7 and 8 show a -constructional example of the spraying nozzle in which a rotational movement around the nozzle needle d is imparted to the material to be sprayed by means of swirl grooves f which are provided on the needle side of the nozzle needle piston b in that space c of the nut z' which is closed by the piston b and into which the nozzle needle d projects; the annular exit surface formed by the hole e of the nozzle hole nut i and the nozzle needle projecting into the said hole may be constantly varied by the relative displacement of the said nut in relation to the said needle. The spinning chamber of the nut i changes from a cylindrical portion c into a conical portion c' which is disposed on the side of the nozzle hole e. Provided on the side which is opposite the said spinning chamber with respect to the nozzle hole is a cylindrical cavity c which opens outwardly. Of the four swirl grooves f arranged on the nozzle needle piston b, the grooves which are next to one another are arranged at right-angles to one another and all are arranged eccentrically of the longitudinal axis of the piston b on the surface thereof and connect the chamber of the nut i with an annular chamber on the surface of the piston b, which chamber e' leads the material to be sprayed into the pressure chamber g through a bore f' which is arranged at right-angles to the longitudinal axis of the nozzle needle piston. The swirl chamber c of the nozzle hole nut i is sealed off in the outward direction by a packing ring h provided in the surface of the nozzle needle piston b and the nut i is held in position relatively to said piston b by means of a threaded connection; that end of the nozzle needle piston b which faces the spray gun is rigidly connected to the outer end of the pressure pump cylinder 12 of the spray-gun.

I claim:

1. In a spray gun operating without the use of cornpressed air, a casing, an electromagnet supported by the casing, a source of liquid to be sprayed, a piston pump directly communicating with the liquid to be sprayed, a thrust bolt operatively associated with the piston pump, an armature adapted to be oscillated by the electromagnet, one end of the armature bearing against the thrust bolt to transmit the oscillations of the armature to the piston pump, means defining a bore in the casing approximately perpendicular to the armature and adjacent to the other end of the armature, a pin in the bore and operatively connected to the armature adjacent to the other end of the armature, spring means within the bore urging the pin in the direction of the armature whereby said other end of the armature is resiliently mounted, manipulable means threaded into the bore and bearing against the spring means to adjust the tension of the spring means, means regulating the stroke of the piston pump to control the flow of liquid to be sprayed, a liquid storage chamber to which liquid is supplied under pressure by the piston pump, and a spray nozzle communicating with the storage chamber.

2. In a spray gun operating without the use of compressed air, the combination as set forth in claim 1, wherein one side of the other end of the oscillating armature bears against the bottom end of the core of the electromagnet while the opposite side of the other end and said manipulable means being defined by a screw threaded into the bore.

3. In a spray gun operating Without the use of compressed air, the combination as set forth in claim l, wherein the upper end of the oscillating armature is provided on that side facing the core of the electromagnet with a longitudinal slot in which engages the thrust bolt, and the spherical end of an adjusting bolt, which is tted inside an adjusting screw and is guided in the head thereof, bears against that spherical depression in the oscillating armature which is opposite the said longitudinal slot in said armature, and that an adjusting spring also incorporated inside the adjusting screw urges the spherical end of the adjusting bolt against the oscillating armature.

4. In a spray gun operating without the use of compressed air, the combination as set forth in claim l, wherein the bottom extended end of the oscillating armature is pivotally connected to the pin which is guided in the bore of a hollow bolt in screw-threaded connection with the casing, and wherein, under the action of the spring means provided in the said bore, the other end of the oscillating armature is urged by means of the pin against the bottom end of the core of the electromagnet.

5. In a spray gun operating without the use of com pressed air, the combination as set forth in claim 1, wherein the outer end of the pressure pump cylinder is provided with a locking nut in which is tted the cylindrical spraying nozzle, which closes a swirl chamber by means of its end facing the nozzle hole and is formed on the edge thereof contacting the inside surface of the swirl chamber along a circular line with a large number of notches arranged eccentrically with respect to the nozzle axis.

6. In a spray gun operating without the use of compressed air, the combination as set forth in claim 5, wherein that edge of the spraying nozzle element which contacts the conical inside surface of the swirl chamber on a circular line is provided with at least six notches which open into a swirl chamber at a predetermined angle to the radius, which is defined by the outer entrance point of the notches.

7. In a spray gun operating without the use of compressed air, the combination as set forth in claim 1, wherein the outer end of the pressure pump cylinder is provided with a locking nut in which is disposed the spraying nozzle which has at its outer end a removable cap in which is located a part of a swirl chamber and the nozzle hole.

8. A spray gun as defined in claim 1 wherein the other end of the armature is pivotally connected to the pin which is guided in the bore of a hollow bolt threadedly connected to the casing, the spring means within the bore urging the other end of the armature against the bottom end of the electromagnet core, and the angle between the piston pump axis and the center line of the contact surface of the electromagnet being more than 90 degrees.

9. In a spray gun operating without the use of compressed air, the combination which comprises a source of liquid to be sprayed, an electromagnet, an armature oscillated by the electromagnet, a piston pump directly communicating with the liquid to be sprayed and actuated by the oscillated armature, means for regulating the stroke of the piston pump for controlling the ow of liquid to be sprayed, means resiliently mounting one end of said armature, a thrust bolt operatively associated with the piston pump, the other end of said armature bearing against the thrust bolt which transmits the oscillations of the said armature to the piston of the pump, a liquid storage chamber to which liquid is supplied under pressure by the piston, and a spray nozzle communicating with said storage chamber, the angle between the pump piston axis and the centre line of the Contact surface of the electromagnet being somewhat more than 90.

10. In a spray gun operating without the use of compressed air, a casing, an electromagnet supported by the casing, a source of liquid to be sprayed, a piston pump directly communicating with the liquid to be sprayed, a thrust bolt operatively associated with the piston pump, an armature adapted to be oscillated by the electromagnet, one end of the armature bearing against the thrust bolt to transmit the oscillations of the armature to the piston pump, one side of the other end of the oscillating armature bears against the bottom end face of the core of the electromagnet, the opposite side of the other end of the armature being formed with a spherical depression, means defining a bore in the casing approximately perpendicular to the armature and adjacent to the other end of the armature, a hollow bolt threaded into the bore, a pin guided in the hollow bolt and having a spherical end bearing in the depression of the armature, spring means within the hollow bolt urging the end of the pin in the depression whereby the other end of the armature is forced against the bottom end face of the electromagnet, means regulating the stroke of the piston pump to control the flow of liquid to be sprayed, a liquid storage chamber to which liquid is supplied under pressure by the piston pump, and a spray nozzle communicating with the storage chamber.

ll. In a spray gun operating without the use of compressed air, the combination as set forth in claim 10, wherein the upper end of the oscillating armature is reduced as far as its centre on the side thereof facing the thrust bolt and is formed in this surface with a longitudinal slot which is engaged by the thrust bolt, and that the spherical end of an adjusting bolt bears on that at side of the oscillating armature which is opposite the said longitudinal slot, said bolt being reduced in diameter to accommodate an adjusting spring and being guided at its inner and outer ends in an adjusting screw which is capable of being adjusted by a threaded connection in the housing.

l2. A spray gun as defined in claim 10 wherein the angle between the pump piston axis and the contact surface of the electromagnet is more than degrees.

13. In a spray gun operating without the use of compressed air, a casing, an electromagnet supported by the casing, a source of liquid to be sprayed, a piston pump directly communicating with the liquid to be sprayed, a thrust bolt operatively associated with the piston pump, an armature adapted to be oscillated by the magnet, means resiliently mounting the lower end of the armature to the casing, the upper end of the armature being provided with means engageable with the thrust bolt, such engageable means including a longitudinal slot on the side of the armature facing the thrust bolt which is engaged by the thrust bolt, this upper end being cut away as far as its centre line of the side thereof opposite the said slot, an adjusting bolt having a spherical end bearing against the cut-away flat side of the armature and which is reduced in diameter to accommodate an adjusting spring, an adjusting screw which is adapted to be adjusted by a screw-threaded connection in the casing and which guides the inner and outer ends of the bolt, a liquid storage chamber to which liquid is supplied under pressure by the piston pump, and a spray nozzle communicating with the storage chamber.

14. A spray gun as defined in claim 13 wherein the angle between the pump piston axis and the center line of the contact surface of the electromagnet is more than 90 degrees.

References Cited in the le of this patent UNITED STATES PATENTS 2,410,692 Strobell Nov. 5, 1946 2,462,001 Rapisarda Feb. 15, 1949 2,494,837 Simmons Ian. 17, 1950 2,704,690 Eichenauer Mar. 22, 1955 FOREIGN PATENTS 259,232 Switzerland June 1, 1949 625,419 Great Britain June 28, 1949 855,826 Germany Nov. 17, 1952 

